Core for rotary electric machines and method of manufacturing the same

ABSTRACT

The present invention has an object to provide a stator core which assures a favorable workability for coupling core segments and has a favorable magnetic characteristic even when the stator core is composed by coupling core segments which are composed by laminating core division sheets. 
     The manufacturing method of a core for rotary electric machines and a core according to the present invention are configured to form a coupling convexity having an arc-like planar shape and a coupling concavity engageable with the coupling convexity on core segments, compose a serial core segment assembly by engaging the coupling convexity on one of adjacent core segments with the coupling concavity formed on the other core segment so as to be rotatable over 180 degrees, and form a magnetic circuit by bending the serial core segment into an annular form.

This application is a Rule 1.53(b) Divisional Application of U.S. Ser.No. 08/929,135, filed Sep. 5, 1997.

FIELD OF THE INVENTION

The present invention relates to a manufacturing method of a core forrotary electric machines which is composed of laminated magnetic steelsheets.

BACKGROUND OF THE INVENTION

As conventional basic manufacturing methods of stator cores for rotaryelectric machines, there is a first method by which a cylindrical coreis manufactured by punching out annular sheet cores by press work andlaminating these sheet cores.

This first manufacturing method by which the annular sheet cores arepunched out by the press work produces waste portions inside and outsideof the sheet cores, thereby lowering yield.

A second manufacturing method, which improves the yield, is illustratedin FIGS. 20(a) through 20(d).

According to the second method, a core division sheet 1 which has anengaging concavity 1 a and an engaging convexity 1 b as shown in FIG.20(a) is first punched out by press work. A core segment 2 is composedby laminating such core division sheets 1 as shown in FIG. 20(b), theengaging convexity 1 b of the core segment 2 is positioned against oneend of the engaging concavity 1 a of an adjacent core segment 2 as shownin FIG. 20(c) and the convexity 1 b is slid or inserted into theconcavity 1 a for coupling the core segments 2, thereby forming acylindrical stator core 3, as shown in FIG. 20(d).

DISCLOSURE OF THE INVENTION

The second manufacturing method by which the divided core sheets 1 arepunced out by the press work does not produce waste portions unlike thefirst manufacturing method and provides a favorable yield, but poses aproblem that workability is low at the coupling stage shown in FIG.20(c). Speaking of a measure to obtain a favorable stator core 3 bylowering magnetic reluctance, it is necessary to reduce clearancebetween the coupled core segments, including the concavity 1 a and theengaging convexity 1 b, so as to eliminate a play among the coupled coresegments 2, but a smaller play will require higher dimensional precisionfor coupling the core segments 2.

Further, a stronger inserting force is required at a stage to engage astarting end of the engaging concavity with one end of the engagingconvexity and slide the core segment 2 since the engaging convexity isinserted while causing friction not only between the engaging concavity1 a and the engaging convexity 1 b but also over the entire joinedsurfaces including those of the engaging concavity and the engagingconvexity.

A primary object of the present invention is to provide a stator corewhich allows core segments to be coupled with high workability and hasfavorable magnetic characteristics even when the stator core ismanufactured by punching out core division sheets by press working andcoupling core segments formed by laminating the divided core sheets soas to obtain a favorable blanking yield.

A method of manufacturing a core for rotary electric machines accordingto the present invention is configured to compose serial core segmentassembly by coupling a plurality of core segments which are composed oflaminated core division sheets, and then form a cylindrical core bybringing both ends of the serial core segment assembly into contact witheach other so as to bend it into an annular form.

According to the present invention, it is possible to obtain stator corewhich assures a high blanking yield, high workability for core segmentcoupling and a favorable magnetic characteristics.

A method of manufacturing a core for rotary electric machines, accordingto a first aspect of the present invention includes forming a pluralityof core segments by laminating core division sheets on which tees areformed, forming a serial core segment assembly by coupling adjacent coresegments with one another, bend the serial core segment assembly into anannular form so that yokes of all the adjacent core segments are broughtinto contact with one another and bringing yokes of core segmentslocated at both ends of the serial core segment assembly into contactwith each other, thereby forming a magnetic circuit.

A method of manufacturing a core for rotary electric machines, accordingto a second aspect of the present invention, includes coupling adjacentcore segments with each other at a location which will form an outercircumference when the magnetic circuit is formed by bending the serialcore segment assembly into the annular form at the stage to compose theserial core segment assembly by coupling the adjacent core segments withone another.

A method of manufacturing a core for rotary electric machine, accordingto a third aspect of the present invention, includes fixing both theends of the serial core segment assembly by welding or cementing them toeach other after the magnetic circuit is formed by bending the serialcore segment assembly into the annular form and bringing the yokes atboth the ends of the serial core segment assembly into contact with eachother.

A method of manufacturing core for rotary electric machine, inaccordance with a fourth aspect of the present invention, includescoupling both the ends of the serial core segment assembly with eachother using a coupling device after the magnetic circuit is formed bybending the serial core segment assembly into the annular form andbringing the yokes of the core segments located at both the ends of theserial core segment assembly into contact with each other.

A method of manufacturing a core for rotary electric machines, accordingto a fifth aspect of the present invention includes laminating coredivision sheets on which tees are formed, molding resin on surfaces ofthe core segments except end surfaces of yokes thereof, forming a serialcore segment assembly by coupling adjacent core segments with oneanother, bend the serial core segment assembly into an annular form sothat yokes of all adjacent core segments are brought into contact withone another, bring yokes of core segments located at both the ends ofthe serial core segment assembly into contact with each other forforming a magnetic circuit and coupling both the ends of the serial coresegment assembly by welding the molded material at both the ends of theserial core segment assembly.

A method of manufacturing a core for rotary electric machine, accordingto a sixth aspect of the present invention, includes forming a pluralityof core segments by laminating core division sheets on which tees areformed, forming a serial core segment assembly by coupling adjacent coresegments with one another, molding resin on the surfaces of the serialcore segment assembly except end surfaces of yokes of the core segments,bending the serial core segment assembly into an annular form so thatyokes of all the adjacent core segments are brought into contact withone another, forming a magnetic circuit by bringing yokes of coresegments located at both the ends of the serial core segment assemblyinto contact with each other and couple both the ends of the serial coresegment assembly with each other by welding the molded material at boththe ends of the serial core segment assembly.

A method of manufacturing a core for rotary electric machines, accordingto a seventh aspect of the present invention, includes forming aplurality of core segments by laminating core division sheets on whichtees are formed, forming a serial core segment assembly by couplingadjacent core segments with one another, bending the serial core segmentassembly into an annular form so that yokes of all adjacent coresegments are brought into contact with one another, forming a magneticcircuit by bringing yokes of the core segments disposed at both ends ofthe serial core segment assembly into contact with each other and coupleboth the ends of the serial core segment assembly with each other bymolding resin on the serial core segment assembly bent in the annularform.

A method of manufacturing a core for rotary electric machines, accordingto an eighth aspect of the present invention, includes coupling both theends of the serial core segment assembly with each other by engaging afirst engaging portion formed at one end of the serial core segmentassembly with a second engaging portion formed at the other end of theserial core segment assembly after the magnetic circuit is formed bybending the serial core segment assembly into the annular form andbringing the yokes of the core segments located at both the ends of theserial core segment assembly into contact with each other.

A method of manufacturing a core for rotary electric machines, accordingto a ninth aspect of the present invention, includes coupling both theends of the serial core segment assembly by overlapping and engagingfirst and second engaging portions in a radial direction of the serialcore segment assembly bent in the annular form.

A method of manufacturing core for rotary electric machines, accordingto a tenth aspect of the present invention, includes coupling both theends of the serial core segment assembly by overlapping and engaging thefirst and second engaging portions laminated in the laminated directionof the core division sheets.

A core for rotary electric machines, according to an eleventh aspect ofthe present invention, comprises a core for rotary electric machineswhose magnetic circuit is formed by forming a plurality of core segmentsof laminated core division sheets having tees formed thereon, couplingthe core segments with one another so as to form a serial core segmentassembly, bending the serial core segment assembly into an annular formso that yokes of all adjacent core segments are brought into contactwith one another and bringing yokes of core segments located at bothends of the serial core segment assembly into contact with each other,characterized in that coupling portions for coupling adjacent coresegments with one another are disposed over the entire region in thelaminated direction of the core segments.

A core for rotary electric machines, according to a twelfth aspect ofthe present invention comprises a core for rotary electric machineswhose magnetic circuit is formed by forming a plurality of core segmentsof laminated core division sheets having tees formed thereon, couplingthe core segments with one another so as to form a serial core segmentassembly, bending the serial core segment assembly into an annular formso that yokes of all adjacent core segments are brought into contactwith one another and bringing yokes of core segments located at bothends of the serial core segment assembly into contact with each other,characterized in that coupling portions for coupling the adjacent coresegments to one another are formed in a partial region in the laminateddirection of the core division sheets.

A core for rotary electric machines, according to a thirteenth aspect ofthe present invention, comprises a core having a concavity formed on anend surface of the yoke of the core segment over the entire region inthe laminated direction of the core division sheets as coupling portionsfor coupling adjacent core segments with one another and a convexity isformed on the other end surface of the yoke of the core segment at alocation corresponding to the concavity over a partial region in thelaminated direction of the core division sheets.

A method of manufacturing a core for rotary electric machines of thepresent invention is a method according to claim 1 or 2, characterizedin that it is configured to engage a coupling convexity which is formedon one of adjacent core segments and has an arc-like tip in a planarshape with the other core segment rotatably over 180 degrees so that anarm connecting a root to a tip of the coupling convexity of the coresegment will not be plastically deformed at the stages to compose theserial core segment assembly by engaging the coupling convexity formedon the core segment with the other core segment, and to form themagnetic circuit by bending the serial core segment assembly into theannular form and bringing the yokes of the core segment located at boththe ends of the serial core segment assembly into contact with eachother.

A method of manufacturing a core for rotary electric machines, accordingto a fifteenth aspect of the present invention, includes engaging acoupling convexity which is formed on one of adjacent core segments andhas an arc-like tip in a planar shape with the other core segmentrotatably within a defined range over 180 degrees and allow an armconnecting a root to the tip of the coupling convexity of the coresegment to be plastically deformed in the course of the bending of theserial core segment assembly into the annular form at the stages tocompose the serial core segment assembly by engaging the couplingconvexity on one of adjacent core segments with the other core segment,and to form the magnetic circuit by bending the serial core segmentassembly into the annular form and bringing the yokes of the coresegments located at both the ends of the serial core segment assemblyinto contact with each other.

A method of manufacturing a core for rotary electric machines, accordingto a sixteenth aspect of the present invention, includes allowing an armconnecting a root to a tip of the coupling convexity to be plasticallydeformed while the coupling convexity formed on one of adjacent coresegments is fitted into the other core segment and the serial coresegment assembly is bent into the annular form at the stages to composethe serial core segment assembly by engaging the coupling convexityformed on one of adjacent core segments with the other core segment, andto form the magnetic circuit by bending the serial core segment assemblyinto the annular form and bringing the yokes of the core segmentslocated at both the ends of the serial core segment assembly intocontact with each other.

A method of manufacturing a core for rotary electric machines, accordingto a seventeenth aspect of the present invention, includes pressing orinserting the coupling convexity toward depth of the coupling concavitywhile the arc-shaped tip of the coupling convexity formed on one of theadjacent core segments is engaged with the arc-shaped coupling concavityformed in the other core segment and the serial core segment assembly isbent into the annular form at the stages to compose the serial coresegment assembly by engaging the coupling convexity formed on one of theadjacent core segments with the other core segment, and forming themagnetic circuit by bending the serial core segment assembly into theannular form and bringing the yokes of the core segments located at boththe ends of the serial core segment assembly into contact with eachother.

A method of manufacturing a core for rotary electric machines, accordingto an eighteenth aspect of the present invention, includes couplingadjacent core segments with each other by using a coupling pin andallowing the coupling pin to be deformed for bending the serial coresegment assembly into the annular form at the stages to compose theserial core segment assembly by engaging the coupling convexity formedon one of adjacent core segments with the other core segment, and toforming the magnetic circuit by bending the serial core segment assemblyinto the annular form and bringing the yokes of the core segmentslocated at both the ends of the serial core segment assembly intocontact with each other.

A method of manufacturing a core for rotary electric machines, accordingto a nineteenth aspect of the present invention, includes using acoupling pin as the coupling device.

A method of manufacturing a core for rotary electric machines, accordingto a twentieth aspect of the present invention, includes continuouslywinding a wire in series around a plurality of tees of the serial coresegment assembly and form a magnetic circuit by bending the serial coresegment assembly having the continuous windings into an annular form.

A method of manufacturing a core for rotary electric machines, accordingto a twenty-first aspect of the present invention, includes fixing bywelding portions which are to form outer circumferences of the couplingportions of the serial core segment assembly after the magnetic circuitis composed by bending the serial core segment assembly into the annularform and bringing the yokes of the core segments located at both theends of the serial core segment assembly into contact with each other.

A method of manufacturing a core for rotary electric machines, accordingto a twenty-second aspect of the present invention, including forming aplurality of core segments by laminating core division sheets on whichtees are formed, forming a serial core segment assembly by couplingadjacent core segments with one another, mounting an insulator made ofresin on each core segment of the serial core segment assembly, bendingthe serial core segment assembly into an annular form so that yokes ofall adjacent core segments are brought into contact with one another,forming a magnetic circuit by bringing yokes of core segments located atboth ends of the serial core segment assembly into contact with eachother, and coupling both the ends of the serial core segment assembly bywelding the insulators located at both the ends of the serial coresegment assembly.

A method of manufacturing a core for rotary electric machines, accordingto a twenty-third aspect of the present invention, includes to forciblyexpanding a concavity which is formed at one end of the serial coresegment assembly and couple both ends of the serial core segmentassembly by applying a pressure to outside the forcibly expandedconcavity after a convexity formed on the other end of the serial coresegment assembly is inserted into the forcibly expanded concavity in aradial direction of the serial core segment assembly bent in the annularform.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1(a) through 1(d) are diagrams illustrating steps of a firstembodiment of the manufacturing method according to the presentinvention;

FIGS. 2(a) through 2(d) are diagrams descriptive of core segments to belocated at ends of a serial core segment assembly in the firstembodiment;

FIG. 3 is a perspective view of a coupled portion of both ends of theserial core segment assembly in the first embodiment;

FIGS. 4(a) and 4(b) are perspective views illustrating a method tocouple both the ends of the serial core segment assembly and concreteshapes of contact surfaces in the first embodiment;

FIGS. 5(a) through 5(c) are diagrams illustrating steps for coupling ina second embodiment of the present invention;

FIGS. 6(a) and 6(b) are diagrams illustrating steps for coupling in athird embodiment of the present invention;

FIGS. 7(a) and 7(b) are diagrams illustrating steps for coupling in aforth embodiment of the present invention;

FIGS. 8(a) through 8(d) are diagrams illustrating steps for coupling ina fifth embodiment of the present invention;

FIGS. 9(a) and 9(b) are diagrams illustrating steps for coupling in asixth embodiment of the present invention;

FIGS. 10(a) and 10(b) are diagrams illustrating main members in thesixth embodiment;

FIGS. 11(a) and 11(b) are diagrams illustrating steps for coupling bothends of a serial core segment assembly in a seventh embodiment of thepresent invention;

FIGS. 12(a) through 12(e) are diagrams illustrating steps for couplingboth ends of a serial core segment assembly in an eighth embodiment ofthe present invention;

FIGS. 13(a) and 13(b) are diagrams illustrating steps for coupling bothends of a serial core segment assembly in a ninth embodiment of thepresent invention;

FIGS. 14(a) and 14(b) are diagrams illustrating steps for coupling bothends of a serial core segment assembly in an eleventh embodiment of thepresent invention;

FIGS. 15(a) and 15(b) are diagrams illustrating steps for coupling bothends of a serial core segment assembly in a fourteenth embodiment of thepresent invention;

FIG. 16 is a diagram illustrating an appearance of an insulator andassembling steps therefor in the fourteenth embodiment;

FIGS. 17(a) and 17(b) are diagrams illustrating coupling steps for aserial core segment assembly in a fifteenth embodiment of the presentinvention;

FIGS. 18(a) and 18(b) are perspective views illustrating coupling stepsfor a serial core segment assembly in a sixteenth embodiment of thepresent invention;

FIG. 19 is a perspective view illustrating coupled portions of a serialcore segment assembly in a seventeenth embodiment of the presentinvention; and

FIGS. 20(a) through 20(d) are diagrams illustrating steps of aconventional method of manufacturing a core.

DESCRIPTION OF THE EMBODIMENTS

The manufacturing method according to the present invention will now bedescribed with reference to the embodiments illustrated in FIGS. 1(a)through 19.

First Embodiment

FIGS. 1(a) through 4(b) illustrate the first embodiment of the presentinvention. The first embodiment is a manufacturing method of a statorcore which has 24 slots.

First, a first core division sheet 4 a shown in FIG. 1(a), and secondand third core division sheets 4 b and 4 c shown in FIGS. 2(a) and 2(c)are formed by punching a magnetic steel plate by press working.Reference numeral 5 represents a tee which is to be used as anelectrode. Sides of the core division sheets 4 a through 4 c, whichlater constitute yokes, have an angle α set in accordance with afinished form of the 24 slots.

By laminating the first core division sheet 4 a in a number required forobtaining thickness of a core in a finished form, 22 core segments 7 aare formed in the first embodiment. By laminating the division coresheets 4 a as described above, a concavity 8 a is formed in one endsurface of the yoke 6 over the entire region in the laminated directionand a convexity 8 b is formed in the other end surface of the yoke 6over the entire region in the laminated direction at a locationcorresponding to the concavity 8 a.

Similarly, a core segment 7 b shown in FIG. 2(b) is formed by laminatingthe second core division sheet 4 b in a required number described above.The core segment 7 b has the convexity 8 b formed in one end surface ofthe yoke 6 over the entire region in the laminated direction but doesnot have the concavity 8 a in the other end surface unlike the coresegment 7 a.

Similarly, a core segment 7 c shown in FIG. 2(d) is formed by laminatingthe third core division sheet 4 c in the required number describedabove. The core segment 7 c has the concavity 8 a formed in one endsurface the yoke 6 over an entire region in the laminated direction, butdoes not have the convexity 8 b in the other end surface of the yoke 6unlike the core segment 7 a.

Then, a serial core segment assembly 9 is formed by connecting 22 coresegments 7 a in series as shown in FIG. 1(c), and coupling the coresegment 7 b and the core segment 7 c with both ends of the core segments7 a.

Speaking concretely, two adjacent core segments are engaged by insertingor sliding the convexity 8 b of one core segment into the concavity 8 aof the other core segment as shown in FIG. 20(c). As coupling portionsin the first embodiment, a round tip is formed at a tip of the convexity8 b and a protrusion 10 is formed on a portion of the yoke located onthe side of the tee so that the concavity 8 a engages with an outercircumference of the tip of the convexity 8 b at an angle exceeding 180degrees. Further, a slant portion 11, or protrusion-adjoining portion11, having an angle corresponding to the protrusion 10 is formed on theyoke at the root of the convexity 8 b on the side of the tee.

When the serial core segment assembly 9, formed as described above, isbent so as to locate the tees 5 inside, the coupling portions rotatesmoothly around the tips of the convexities 8 b and an annular magneticcircuit is formed as shown in FIG. 1(d) by bringing the yokes of thecore segment 7 b and the core segment 7 c into contact with each other.

FIG. 3 shows details of a location where the core segment 7 b and thecore segment 7 c are brought into contact with each other. At thislocation, the core segment 7 b and the core segment 7 c are coupled toeach other by welding end surfaces as shown in FIG. 4(a). Referencenumeral 12 represents a welded location.

For more precisely positioning the core segment 7 b to the core segment7 c when the serial core segment assembly is bent into an annular form,it is desirable to preliminarily form a positioning protrusion 13 a onthe yoke of either the second or third core division sheet 4 b or 4 cand a receiving concavity 13 b for engagement with the protrusion 13 ain the other core division segment as shown in FIG. 4(b).

Although the end surfaces of the core segments 7 b and the core segment7 c are welded for coupling the core segment 7 b and the core segment 7c with each other in the first embodiment described above, the portionswhich are brought into contact with each other can be fixed by weldingan outer circumference 14 of these portions without welding the endsurfaces.

In the first embodiment which is configured as described above, the coresegment 7 b and the core segment 7 c can be coupled with an insertingforce which is weaker than that conventionally required since the coresegment 7 b slides in the laminated direction while causing frictiononly between an inner circumferential surface of the concavity 8 a andan outer circumference of the tip of the convexity 8 b, and almost allportions of the yokes are free from friction at the stage to couple thecore segments 7 a, 7 b and 7 c.

Further, the serial core segment assembly 9 can be bent into acylindrical form with a weak force since the coupling portions arerotate smoothly around the tips of the convexities 8 b at the stage tobend the serial core segment assembly into the annular form.Furthermore, favorable yokes having a low magnetic resistance can belocated close to the roots of the tees 5 and a stator core having afavorable magnetic characteristic can be obtained, since the coresegments are coupled to one another with the coupling portions formed onthe portions which are to form an outer circumference when the magneticcircuit is formed by bending the serial core segment assembly 9 into theannular form.

While comparing the first embodiment of the preferred manufacturingmethod, with the conventional manufacturing method, description will bemade of the excellence in winding work of the manufacturing methodaccording to the first embodiment.

After a stator core has been finished in the cylindrical form, wires arecontinuously wound while passing them through slight gaps between tipsof the tees 5. However, workability is low when the wires are woundwhile passing them through the gaps between the tips of the tees.

The conventional manufacturing method described with reference to FIG.20 permits winding wires without passing them through the slight gapsbetween tips of the tees when the wires are wound around the tees 5 ofeach core segment 2 in the condition shown in FIG. 20(b) where the coresegments have not been coupled yet and terminal treatment is carried outfor serial connection of the wires wound separately around the tees 5after the core is finished in the cylindrical form shown in FIG. 20(d).

The first embodiment of the preferred manufacturing method, which isconfigured to wind a wire continuously around the tees 5 in thecondition of the serial core segment assembly and form the magneticcircuit by bending the serial core segment assembly having the woundwire into the annular form, not only permits winding the wire withoutpassing it through the gaps between the tips of the tees of the statorcore finished in the annular form as shown in FIG. 1(d) but alsorequires no tedious terminal treatment unlike the conventionalmanufacturing method, thereby assuring favorable winding workability.

Further, the first embodiment of the preferred manufacturing method,allows slot openings to be reduced, thereby capable of enhancing aneffective magnetic flux and lowering cogging torques of motors havingpermanent magnets.

Though description has been made of the first embodiment taking thestator core which has the 24 tees as an example, the manufacturingmethod is applicable also to stator cores which have tees (slots) indifferent numbers.

Second Embodiment

FIGS. 5(a) through 5(c) show the second embodiment of the presentinvention. Though the convexities 8 b are not plastically deformed atthe stage to form the cylindrical stator core by bending the serial coresegment assembly 9 into the annular form in the first embodiment,convexities are partially deformed plastically in the second embodiment.FIGS. 5(a) through 5(c) exemplify a stator core which has 6 slots.

FIG. 5(a) illustrates a condition immediately after core segments arecoupled in series. The core segments smoothly rotate around a tip of theconvexity 8 b and the convexity 8 b is not plastically deformed at aninitial stage to bend the serial core segment assembly 9 into theannular form but, once a tip of a protrusion 10 is brought into contactwith an arm 15 which connects a tip of the convexity 8 b to a yoke 6,subsequent bending causes plastic deformation of the arm as shown inFIG. 5(c) to finish a stator core 3 in a cylindrical form. In the otherrespects, the second embodiment remains unchanged from the firstembodiment.

Third Embodiment

FIGS. 6(a) and 6(b) illustrate the third embodiment of the presentinvention. Though the convexities 8 b are not plastically deformed atthe stage to form the cylindrical stator core by bending the serial coresegment assembly 9 into the annular form in the first embodiment,convexities are partially deformed plastically in the third embodiment.FIGS. 6(a) and 6(b) exemplify a stator core which has 6 slots.

FIG. 6(a) shows a condition immediately after core segments are coupledin series wherein a convexity 8 b having a triangular tip is engagedwith a concavity 8 a formed in an adjacent core segment.

When starting bending of a core segment assembly 9 into an annular form,an arm 15 which connects the tip of the convexity 8 b to a yoke 6 isplastically deformed as shown in FIG. 6(b) to finish a stator core in acylindrical form.

The third embodiment remains unchanged from the first embodiment in theother respects.

The tip of the convexity 8 b may not be triangular and can have anothershape which does not permit rotation thereof, concretely rectangular orelliptical shape.

Fourth Embodiment

FIGS. 7(a) and 7(b) show the fourth embodiment of the present invention.In contrast to the first embodiment described above while exemplifyingcore division sheets on which the convexities having round tips areformed, the fourth embodiment is configured to form, as a convexity 8 b,an integral arm 16 b which has an arc shape around an angle P of anouter circumference from a portion constituting a yoke of a coredivision sheet to a tip. As the concavity 8 a corresponding to this arm16 b, an arc-shaped notch 16 a is formed around the angle P of the outercircumference.

When starting to bend a serial core segment assembly 9 into an annularform, the arc-shaped arm 16 b is pressed or inserted into the arc-shapednotch 16 a and a cylindrical stator core is finished as shown in FIG.7(b). The fourth embodiment remains unchanged from the first embodimentin the other respects.

Fifth Embodiment

FIGS. 8(a) through 8(d) illustrate the fifth embodiment of the presentinvention. In contrast to the fourth embodiment wherein the arc-shapedarm 16 b is formed integrally with the core division sheet as theconvexity, the fifth embodiment is configured to form an arc-shaped arm16 b separately from a core division sheet 4.

As shown in FIG. 8(a), formed in the core division sheet 4 are an armsetting notch 17 at one end of a portion which is to constitute a yokeand an notch 16 a having an arc shape around an angle P of an outercircumference.

A plurality of core segment bodies 70 are composed by laminating thecore division sheet 4 in a required number as shown in FIG. 8(b). A coresegment 7 is formed by fitting the separately formed arc-shaped armmember 16 b into a groove 18 which is formed in the laminated directionby the arm setting notches formed in the core segment body 70 forsetting the arm.

A serial core segment assembly 9 is composed by coupling the coresegments 7 as shown in FIG. 8(c) and bent into an annular form to finisha cylindrical stator core as in the fourth embodiment.

Though the arc-shaped arm member 16 b is formed by punching outarc-shaped magnetic steel plates and laminating these plates, thismember can be formed not by laminating but by cutting it out as anintegral lump. The fifth embodiment remains unchanged from the fourthembodiment in the other respects.

Sixth Embodiment

FIGS. 9(a) through 10(b) illustrate the sixth embodiment of the presentinvention. Though the coupling portions which couple the core segmentsto compose the serial core segment assembly are composed so as to engagethe convexity 8 b formed at one end of the yoke 6 of the core segmentwith the concavity 8 a formed at the other end of the yoke 6 of theadjacent core segment in the first through fifth embodiments, the sixthembodiment is configured to compose a serial core segment assembly 9 bycoupling adjacent core segments 7 a with a pin 19 as shown in FIG. 9(a)and bend the serial core segment assembly 9 into an annular form,thereby bending the pin 19 so as to finish a stator core having acylindrical form as shown in FIG. 9(b).

Speaking more concretely, holes 20 are formed at both ends of a portionwhich is to constitute a yoke of a core division sheet 4 a as shown inFIG. 10(a) and a plurality of core segments 7 a are composed bylaminating the core division sheet 4 a in a required number.

A serial core segment assembly 9 is composed by disposing the coresegments 7 a and inserting U-shaped pins into the holes 20 of adjacentcore segments as shown in FIG. 10(b). When the serial core segmentassembly 9 is bent into an annular form, the pins 19 are deformed tofinish a cylindrical stator core 3 shown in FIG. 9(b).

Seventh Embodiment

FIGS. 11(a) and 11(b) show the seventh embodiment of the presentinvention. In contrast to the first embodiment through the sixthembodiment in each of which both the ends of the serial core segmentassembly are coupled with each other by welding after the magneticcircuit is formed by bending the serial core segment assembly into theannular form and bringing the yokes of the core segments disposed atboth the ends of the serial core segment assembly into contact with eachother, the seventh embodiment is configured to couple both ends of aserial core segment assembly 9 by engaging a first engaging portion 21 aformed at one end of the serial core segment assembly 9 with a secondengaging portion 21 b formed at the other end as shown in FIG. 11(b).

Eighth Embodiment

FIGS. 12(a) through 12(e) illustrate the eighth embodiment of thepresent invention.

In contrast to the first embodiment through the sixth embodiment,wherein both the ends of the serial core segment assembly are coupledwith each other by welding after the magnetic circuit is formed bybending the serial core segment assembly into the annular form andbringing the yokes of the core segments disposed at both the ends of theserial core segment assembly into contact with each other, the eighthembodiment is configured to form a serial core segment assembly 9 ofcore segments 7 a which have the same shape as shown in FIGS. 12(a) and12(b), form a magnetic circuit by bending the serial core segmentassembly 9 into an annular form, and forcibly expand a concavity 8 aformed at one end of the serial core segment assembly 9 with a jig 22 ain a direction indicated by an arrow F1 as shown in FIG. 12(c). After aconvexity 8 b formed at the other end of the serial core segmentassembly 9 is inserted in the radial direction into the serial coresegment assembly 9 which is bent in the annular form and press a partialor entire width outside a forcibly expanded concavity 8 aa with a jig 22b in the laminated direction of the core division sheets to shape astator core 3 as shown in FIG. 12(e).

Though the eighth embodiment is configured to forcibly expand theconcavity 8 a formed at the one end of the serial core segment assembly9 after the core segments 7 a are composed into the serial core segmentassembly 9, it is possible to expand the concavity 8 a in each of thecore segment 7 a and then compose the serial core segment assembly 9.

Ninth Embodiment

FIGS. 13(a) and 13(b) illustrate the ninth embodiment.

In contrast to the first through sixth embodiment each of which both theends of the serial core segment assembly are coupled by welding afterthe magnetic circuit is formed by bending the serial core segmentassembly into the annular form and bringing the yokes of the coresegments located at both the ends of the serial core segment assemblyinto contact with each other, the ninth embodiment is configured to formends of core division sheets so as to form concavities 23 a andconvexities 23 b which are alternately flush at both ends a serial coresegment assembly 9 as shown in FIG. 13(a) and put one and of the serialcore segment assembly into the other end for forming a cylindricalmagnetic circuit as shown in FIG. 13(b).

Tenth Embodiment

Though both the ends of the serial core segment assembly are coupledwith each other by welding after the magnetic circuit is formed bybending the serial core segment assembly is bent into the annular formand bringing the yokes of the core segments located at both the ends ofthe serial core segment assembly into contact with each other in each ofthe first embodiment through the sixth embodiment, it is possible tocouple a serial core segment assembly into an annular form by insertinga U-shaped pin 19, which is similar to the pin 19 which is used forcomposing the serial core segment assembly 9 in the sixth embodiment,into a hole formed at one end of the serial core segment assembly and ahole formed at the other end.

Eleventh Embodiment

FIGS. 14(a) and 14(b) show the eleventh embodiment of the presentinvention. Though both the ends of the serial core segment assembly arecoupled with each other by welding, engaging or inserting the U-shapedpin after the magnetic circuit is formed by bending the serial coresegment assembly into the annular form and bringing the yokes of thecore segments located at both the ends of the serial core segmentassembly in each of the first embodiment through the tenth embodiment,the eleventh embodiment is configured to mold resin on surfaces of coresegments of a serial core segment assembly 9, except end surfaces ofyokes, as shown in FIG. 14(a), and form a magnetic circuit by bending aserial core segment assembly 9 into an annular form so that yokes of alladjacent core segments are brought into contact with one another asshown in FIG. 14(b) and bring yokes of core segments 25 a and 25 blocated at both ends of the serial core segment assembly into contactwith each other.

Both the end of the serial core segment assembly 9 which has been shapedinto the annular form are coupled with each other by welding thematerial molded on an outer circumference 26 or end surfaces 25 c and 25d with supersonic waves or similar means.

Twelfth Embodiment

Though the resin is molded selectively at the required locations afterthe serial core segment assembly is formed and both the ends thereof arecoupled with each other by welding the molded material on both the endsof the serial core segment assembly after it is formed into the annularform in the eleventh embodiment, it is possible to mold resin onsurfaces of core segments, except end surfaces of yokes, before they arecoupled into a serial core segment assembly 9, form a serial coresegment assembly 9 by coupling the core segments having the molded resinand couple both ends of the serial core segment assembly by welding themolded material at both the ends of the serial core segment assembly inthe same manner as that in the eleventh embodiment.

Thirteenth Embodiment

Though the resin is molded selectively at the required locations afterthe serial core segment assembly is composed and both the ends of theserial core segment assembly are coupled with each other by weldingafter the serial core segment assembly is bent into the annular form inthe eleventh embodiment, it is possible to couple both ends of a serialcore segment assembly by molding resin on the serial core segmentassembly which is bent into an annular form.

Fourteenth Embodiment

FIGS. 15(a) through 16 show the fourteenth embodiment of the presentinvention.

Though both the ends of the serial core segment assembly are coupledwith each other by welding the material molded on the core segments ineach of the eleventh embodiment and the twelfth embodiment, thefourteenth embodiment is configured to prepare insulators 27, 27 made ofresin as shown in FIG. 16, mount the insulator 27 on each of coresegments of a serial core segment assembly 9 as shown in FIG. 15(a),bend the serial core segment assembly 9 into an annular form so thatyokes of all adjacent core segments are brought into contact with oneanother as shown in FIG. 15(b) and form a magnetic circuit by bringingyokes at ends 28 a and 28 b of the insulators 27 located at both ends ofthe serial core segment assembly 9 into contact with each other.

Further, the insulators 27 located at both the ends of the serial coresegment assembly 9 which is shaped into the annular form can be coupledwith each other by welding an outer circumference or end surfaces 28 cand 28 d of the insulators 27 with ultrasonic waves or the like.

Though the insulators 27, 27 are mounted on each of the core segments 7of the serial core segment assembly 9 in FIGS. 15(a) and 15(b), amagnetic circuit can similarly be formed by mounting the insulators 27,27 on the core segments 7 as shown in FIG. 16, composing the serial coresegment assembly 9 by coupling the core segments on which the insulators27, 27 have been mounted, bending the serial core segment assembly 9into an annular form so that yokes of all adjacent core segments arebrought into contact with one another, and bringing the yokes of thecore segments of the ends 28 a and 28 b of the insulators 27 located atboth the ends of the serial core segment assembly into contact with eachother.

Fifteenth Embodiment

FIGS. 17(a) and 17(b) show the fifteenth embodiment of the presentinvention. Though the adjacent core segments are coupled by engaging thecoupling concavities with the coupling convexities for composing theserial core segment assembly and the magnetic circuit is formed bybending the serial core segment assembly so that the yokes of theadjacent core segments are brought into contact with one another in eachof the embodiments described above, it can be expected to enhancemechanical strength and precision of the annular form of a stator coreby preliminarily forming an engaging protrusion 30 a and an engagingconcavity 30 b at locations of a core division sheet 4 a which are on aside of the tee of the yoke as shown in FIG. 17(a) so that engagingprotrusion 30 a engages with the engaging concavity 30 b as shown inFIG. 17(b) when the serial core segment assembly is bent into theannular form.

Sixteenth Embodiment

FIGS. 18(a) and 18(b) show the sixteenth embodiment of the presentinvention. Though the coupling portions for coupling the core segmentsare formed as the concavity formed at one end of the yoke of the coresegment over the entire width in the laminated direction and theconvexity formed at the other end of the yoke of the core segment overthe entire width in the laminated direction in each of the embodimentsdescribed above, a similar effect can be obtained by forming the similarcoupling portions on end surfaces of partially in the laminateddirection of the core division sheets.

Such an effect can be obtained by preparing and laminating core divisionsheets so as to form a concavity 8 a at one end of a yoke of a coresegment 7 a over the entire width at shown in FIG. 18(a), andconvexities 8 ba and 8 bb at the other end of the yoke of the coresegment 7 a in the laminated direction except a middle portion thereofas shown in FIG. 18(a) or preparing and laminating core division sheetsso as to form a concavity 8 a at one end of a yoke of a core segment 7 aover the entire width in the laminated direction and a convexity 8 bc atthe other end of the yoke of the core segment 7 a at a middle locationin the laminated direction as shown in FIG. 18(b).

By forming such coupling portions for coupling adjacent core segmentswith each other partially on end surfaces of core segments, it ispossible to further reduce friction to be produced by inserting theconvexity 8 b into the concavity 8 a.

Seventeenth Embodiment

FIG. 19 shows the seventeenth embodiment of the present invention.Though the core segments 7 a-7 a, 7 a-7 b and 7 a-7 c are coupled withone another by the engagement, press fitting, insertion or use of theU-shaped pins in each of the first embodiment through the sixthembodiment, the seventeenth embodiment is configured to weld outercircumferences 31 of coupling portions partially or over the entirewidth in a condition where a serial core segment assembly is bent in anannular form as shown in FIG. 19.

It can be expected that the welding enhances mechanical strength of astator core 3 and precision of the annular form thereof.

Though one tee is formed on a core division sheet in the embodimentsdescribed above, the similar effects may be obtained by forming aplurality of tees on one core division sheet, composing core segments bylaminating such core division sheets and composing a serial core segmentassembly by coupling the core segments and bending the serial coresegment assembly into an annular form to finish a cylindrical statorcore.

As is clear from the embodiments described above, configurations definedby claims of the present invention provide particular effects which arementioned below:

The method of manufacturing a core for rotary electric machines,according to a first aspect of the present invention, permits forming acylindrical core of core division sheets, thereby providing a favorableblanking yield. Further, this method is configured to bend a serial coresegment assembly after it is composed by coupling core segments andpermits coupling the core segments in a condition where yokes ofadjacent core segments are free from friction, thereby assuring a highworkability at the stage to couple the core segments. Furthermore, themethod facilitates to bring the yokes of the adjacent core segments intoclose contact so as to remain no gap, thereby permitting loweringmagnetic reluctance and obtaining a favorable magnetic characteristic.

Moreover, the method permits continuously winding a wire around tees ofthe serial core segment assembly and then bending the serial coresegment assembly into an annular form, thereby providing an assemblingworkability higher than that obtained in a case where wires are woundindependently around tees of a core finished in a cylindrical form andthe wires are connected in series by terminal treatments of the wires.

The method of manufacturing a core for rotary electric machines,according to a second aspect of the present invention, permits locatingfavorable yokes having a low magnetic reluctance close to roots of tees,thereby making it possible to obtain a stator core having a favorablemagnetic characteristic.

The method of manufacturing a core for rotary electric machines,according to a third aspect of the present invention, permits stablymaintaining a cylindrical form obtained by bending a serial core segmentassembly into an annular form, thereby facilitating to handle the corein a stage to build it into a frame of a rotary electric machine.

The method of manufacturing a core for rotary electric machines,according to a fourth aspect of the present invention, permits stablymaintaining a cylindrical form obtained by bending a serial core segmentassembly into an annular form, thereby facilitating to handle the coreat a stage to build it into a frame of a rotary electric machine.

The method of manufacturing a core for rotary electric machines,according to a fifth aspect of the present invention, permits stablymaintaining a cylindrical form obtained by bending a serial core segmentassembly into an annular form, thereby facilitating to handle the coreat a stage to build it into a frame of a rotary electric machine.Further, this method allows both ends of the serial core segmentassembly bent in the annular form to be coupled with each other byutilizing a molding material.

The method of manufacturing a core for rotary electric machines,according to a sixth aspect of the present invention, permits stablymaintaining a cylindrical form obtained by bending a serial core segmentassembly into an annular form, thereby facilitating to handle the coreat a stage to build it into a frame of a rotary electric machine.Further, this method allows both ends of the serial core segmentassembly bent into an annular form to be coupled with each other byutilizing a molding material.

The method of manufacturing a core for rotary electric machines,according to a seventh aspect of the present invention, permits stablymaintaining a cylindrical form obtained by bending a serial core segmentassembly into an annular form, thereby facilitating to handle the coreat a stage to assemble it into a frame of a rotary electric machine.Further, this method allows both ends of the serial core segmentassembly bent into an annular form to be coupled with each other byutilizing a molding material.

The method of manufacturing a core for rotary electric machines,according to an eighth aspect of the present invention, permits stablymaintaining a cylindrical form obtained by bending a serial core segmentassembly into an annular form, thereby facilitating to handle the coreat a stage to assemble it into a frame of a rotary electric machine.

The method of manufacturing a core for rotary electric machines,according to a ninth aspect of the present invention, coupling both endsof a serial core segment assembly with each other simply by slightlychanging shapes of core segments located at both the ends of the serialcore segment assembly, thereby facilitating to handle the core at astage to assemble it into a frame of a rotary electric machine.

The method of manufacturing a core for rotary electric machines,according to a tenth aspect of the present invention, allows both endsof a serial core segment assembly with each other simply by slightlychanging manufactured lengths of yokes of core division sheets of coresegments located at both the ends of the serial core segment assembly,thereby facilitating to handle the core at a stage to build it into aframe of a rotary electric machine.

The core for rotary electric machines, according to an eleventh aspectof the present invention, consists of a serial core segment assemblywhich is composed of core segments composed by laminating core divisionsheets having the same shape.

The core for rotary electric machines, according to a twelfth aspect ofthe present invention, permits weakening an inserting force for couplingcore segments though it requires forming and laminating core divisionsheets which have several kinds of shapes.

The core for rotary electric machines according to a thirteenth aspectof the present invention, is comprised of core segments which have nodistinction between front and rear surfaces or can be coupled in anydirection, thereby featuring a high workability.

The method of manufacturing a core for rotary electric machines of thepresent invention allows core segments to be rotated smoothly aroundtips of coupling convexities at a stage to bend a serial core segmentassembly into an annular form, thereby shaping it into a cylindricalform with a slight force.

The method of manufacturing a core for rotary electric machines,according to a fifteenth aspect of the present invention, allows aserial core segment assembly to be bent into an annular form or shapedinto a cylindrical form with a slight force required for plasticdeformation of arms and facilitates to maintain the serial core segmentassembly in the annular form owing to the plastic deformation of thearms.

The method of manufacturing a core for rotary electric machines,according to a sixteenth aspect of the present invention, allows aserial core segment assembly to be bent into an annular form or shapedinto a cylindrical form with a slight force required for plasticdeformation of arms and facilitates to maintain the serial core segmentassembly in the annular form owing to the plastic deformation of thearms.

The method of manufacturing a core for rotary electric machines,according to a seventeenth aspect of the present invention, allows aserial core segment assembly to be bent into an annular form or shapedinto a cylindrical form with a slight force required for pressing orinserting coupling convexities toward depth of coupling concavities.

The method of manufacturing a core for rotary electric machines,according to an eighteenth aspect of the present invention, includescoupling adjacent core segments with each other using a coupling pin andrequires only formation of holes in the core segments for inserting thepin, thereby facilitating to manufacture the core segments as comparedwith core segments which have coupling concavities and convexitiesformed on outer circumferences thereof.

The method of manufacturing a core for rotary electric machines,according to a nineteenth aspect of the present invention, requires onlyformation of holes for inserting coupling pins into core segments to belocated at both ends of a serial core segment assembly, therebyfacilitating to manufacture the core segments as compared with coresegments which have coupling concavities and convexities formed on outercircumferences thereof.

The method of manufacturing a core for rotary electric machines,according to a twentieth aspect of the present invention, includescontinuously winding a wire before a serial core segment assembly isbent into an annular form, thereby facilitating a winding work.

The method of manufacturing a core for rotary electric machines,according to a twenty-first aspect of the present invention, it possibleto expect to enhance mechanical strength of a stator core and precisionof an annular form thereof when a serial core segment assembly is bentinto the annular form or finished in a cylindrical form.

The method of manufacturing a core for rotary electric machines,according to a twenty-second aspect of the present invention, permitsstably maintaining a cylindrical form which is obtained by bending aserial core segment assembly into an annular form and facilitate tohandle a core at a stage to assemble it into a frame of a rotaryelectric machine. Further, this method permits both ends of a serialcore segment assembly bent in an annular form to be coupled with eachother by utilizing an insulator material.

The method of manufacturing a core for rotary electric machines,according to a twenty-third aspect of the present invention, permitscomposing a cylindrical stator core only of core segments which have thesame shape.

What is claimed is:
 1. A core for rotary electric machines including aplurality of non-contiguous core segments manufactured by the sequentialsteps comprising laminating core division sheets having tees, obtaininga magnetic circuit by forming a serial core segment assembly by couplingsaid non-contiguous adjacent core segments with one another and bendingthe serial core segment assembly into an annular form so that yokes ofall the adjacent core segments are brought into contact with one anotherand the yokes of core segments located at both ends of the serial coresegment assembly contact each other, wherein each of said core segmentsincludes first and second coupling portions on first and second sideportions thereof for coupling adjacent core segments with one another,and said first and second coupling portions extend through the thicknessof the corresponding core segment in the laminated direction of the coredivision sheets.
 2. A core for rotary electric machines according toclaim 1, wherein one of said first and second coupling portionscomprises convexities and the other of said first and second couplingportions comprises concavities.
 3. A core for rotary electric machinesaccording to claim 2, wherein the convexities of one core segment arelocated at positions that correspond to the concavities of an adjacentcore segment.
 4. A core for rotary electric machines according to claim2, wherein the convexities of a core segment are located at positionscorresponding to the concavities of an adjacent core segment, and theconvexities comprise rounded tip ends, the concavities are located onprotrusions of yokes, and protrusion-adjoining portions corresponding tothe protrusions are located at portions of the yokes proximal theconvexities.
 5. A core for rotary electric machines including aplurality of non-contiguous core segments manufactured by the sequentialsteps comprising laminating core division sheets having tees, obtaininga magnetic circuit by forming a serial core segment assembly by couplingnon-contiguous adjacent core segments with one another and bending theserial core segment assembly into an annular form so that yokes of allthe adjacent core segments contact one another and the yokes of coresegments located at both ends of the serial core segment assemblycontact each other, wherein each of said core segments includes firstand second coupling portions on first and second side end portionsthereof for coupling adjacent core segments with one another, andwherein a part of one of said first and second coupling portions extendspartially through the thickness of the corresponding core segment in thelaminated direction of the core division sheets.
 6. A core for rotaryelectric machines according to claim 5, wherein said part of said one ofsaid first and second coupling portions comprises convexities andanother part of the other of said first and second coupling portionscomprises concavities.
 7. A core for rotary electric machines accordingto claim 6, wherein the convexities of one core segment are located atpositions that correspond to the concavities of an adjacent coresegment.